That a bridge should earn such a designation points to something older or more significant than a routine river crossing, though the structure sits modestly in a rural landscape where such things can go unremarked for generations.

Grenan itself is a townland with deep historical roots in the Kilkenny countryside, and bridges in this part of Leinster frequently date to the medieval or early post-medieval period, when river crossings were carefully chosen and carefully built, often in association with nearby manorial estates, monastic lands, or routeways connecting market towns. A bridge substantial enough to survive into the modern era, and to attract the attention of architectural or archaeological recorders, would typically be of mortared stone construction, with arched spans designed to manage the seasonal flooding that characterises many Kilkenny watercourses. The precise dating, dimensions, and construction history of this particular crossing are not currently available in the public record, which itself says something about how many such structures remain only partially understood.